Convertible wheeled truck tractor



May 3, 1932. w CHRISTIE 1,856,668

CONVERTIBLE WHEELED TRUCK TRACTOR Original Filed April 30, 1928 5 Sheets-Sheet l as M'W. -W

1932- w. CHRISTIE 1,856,068

CONVERTIBLE WHEELED TRUCK TRACTOR Original Filed April 30, .1928 5 Sheets-Sheet 2 May 3, 1932. w. CHRISTIE 3 3 CONVERTIBLE WHEELED TRUCK TRACTOR Original Filed April 30, 1928 5 Sheets-Sheet 3 0 Wm L Lam;

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CONVERTIBLE WHEELED TRUCK TRACTOR Original Filed April 30, 1928 5 Sheets-Sheet 4 v s wanton May 3, 1932.

May 3, 1932. w. CHRISTIE CONVERTIBLE WHEELED TRUCK TRACTOR Original Filed April 30. 1928 5 Sheets-Sheet 5 i to Patented May 3, 1932 UNITED STATES "Whit-TEE CHRISTIE, OF AVON, NEW JERSEY, ASSIGNOR TO CHARLES R, LORD AND CLAYTON FARRIS, BOTH F NEWARK, NEW JERSEY CONVERTIBLE WHEELED TRUCK TRACTOR n Application filed April 30, 1928, Serial No. 274,097. Renewed September 19, 1981.

This invention relates to improvements in so-called crawler attachments for road vehicles of the general type disclosed in the claim in the copending application of the 3 present applicant, Ser. No. 688,638, filed February 26, 1924. In accordance with the system disclosed therein, road wheels are provided around which may be placed tracks of the track laying type to facilitate operation? function are contemplated and also an im provement in the method of driving the track when applied. More particularly, it is proposed, in accordance with the improvements, cm to provide bogeys at opposite sides of the vehicle, each bogey comprising a wheel of large diameter over which the track passes and a wheel of small diameter which'further distributes the load and insures a more eificient track action. Each bogey is pivoted at a point between the large and small wheels on a stub axle about which the bogey may rock, while the stub axle itself has an arcuate movement about the supporting dead axle which extends transversely of the vehicle :trame, this dead axle itself being pivotally suspended from the frame, so that the greatest degree of compensation and the most eftective load distribution is further assured by the resulting combined motions of all. oi

the parts. The springing of the load as to the bogeys is accomplished by means of substantially vertically disposed springs engaging the supporting arms for the bogeys at points between their axes and the axis of the supporting axle. Resistance to strains tending to change the track centers is oliered yieldingly by the independent springs which are so disposed with respect to the supporting dead axle itself as to effectively apply their force to the dead axle at all times and resist yieldingly a shortening of the track centers. While the two sets of springs referred to are physically independent and are primarily adapted to perform independent functions,

vention, by-forming certain of the links thereof with inwardly depending lugs which are engaged by rollers revolubly carried with the drive wheel, the engaging surfaces of the rollers and lugs being complementary. The principal advantages secured by this method of drive is the reduction of friction and power losses and a self-scavaging sprocket.

These and other objects and advantages will appear at greater length hereinafter in connection with the detailed description of the embodiment illustrated in the accompanying drawings wherein F gure 1 1s a view in side elevation of a road vehicle showing the improvgd attachment wvith the track omitted.

Figure 2 is a view in side elevation on a somewhat larger scale showing the operating and partly in horizontal section showing the pivoted suspension arm for the stub axle of the bogey and taken on the plane indicated by line 22 of Figure 2. v

Figure 3 is a plan view thereof with a track indicated as applied at one side of the vehicle and removed at the other side.

Figure 4 is a detailed fragmentary view in transverse section showing one of the idler wheels and the method of supporting the bogeys and taken on the plane indicated by line ll of Figure 2.

Figure 5 is a detailed sectional view taken transversely through the parts shown in Figure 4 illustrating the relation of the suspension spring to the bogey and taken on the plane indicated by line 5---5 of Figure 2.

Figure 5 is a detailed View in section of tion of the arrows.

relation of the track thereto and theimproved f drive roller and taken on the plane indicated by line 6--6 of Figure 7 looking in the direc- Figure 7 is a fragmentary, detailed view in side elevation showing the improved drive for the tree e As shown in Figure 1, the vehicle a will be provided with front -steering road wheels at and driving wheels (1*. These driving wheels, as shown in Figure 3, are of a dual character, being spaced to receive lugs 1) formed to depend from links I) of a track 6 which may be applied to the drive wheels and to cooperating idler road'wheels a, whenever the character of the terrain makes that advisable. lVhen the tracks are not applied, the vehicle, as a road vehicle, has all of the advantages which flow from application of the load to the road at a relatively great number of points. In the vehicle illustrated, the load is thus transmitted to the road through four wheels at each sideof the vehicle, small idler wheels d being operatively associated with the larger idler wheels 0 in a manner which constitutes one of the principal improvements. .Since parts are duplicated at opposite sides of the vehicle, the description of those at one side only will be suflicient. The wheels cand cl are journalled respectively at 0' and d in spaced frame members 6, the whole, when assembled, constituting what will be hereinafter termed for convenience, a bogey. Through the bogey passes a stub axle 7 about which the frame members 6 may rock, permittin automatically at all times an interaction between the wheels 0 and d by which they may mutually accommodate themselves to operatingconditions. The stub axle f is journalled in a frame, the form of which is best illustrated in Figure'2. This frame includes a longitudinally extending member 9 and an arm 9' secured thereto at its mid-section but curved in the plan so as' to form with the main section 9 a yoke. Thisyoke is pivoted on a dead axleh which extends across the vehicle. The dead axle h is pivotally hung from the side frame members '5 through a i The coil spring is bears against the free end bracket i secured thereto and a pivoted hanger 2' attached to the bracket, as will be clear from Figure 4. Swinging of the hanger 1? is opposed by a coilspring the relation of which to the hanger is shown in Figure 2.

of abell crank lever Z which is pivoted intermediate its ends at Z to the bracket 2" and ally at one end to the bracket 71 and has at.

its other end a nut m threaded thereon for adjustment of the tension of the s ringin a manner which will be obvious.

ell crank lever Z issuch that, taking into account the direction of the forces, its energy is most 'efiiciently applied to the lower end of the bell crank to urge the dead axle k and the large idler wheel 0 away from the driving wheels (1 Thus the distance between their centers is maintained yieldingly at all times and the parts relieved of undue positive pulls and the load itself somewhat cushioned. However, the present improvements provide separate springs for suspending the load 011 the bogeys, such a spring being illustrated at n and being interposed operatively between the chassis frame and the bogey. More particularly, as illustrated in Figures 2 and 5, a spring at isformed as a coil spring seated at its lowerend on a plate n which is pivotally attached to the yoke g to permit self-alignment of the spring under angular movements of the yoke.- The upper end of the spring is seated on a flange 0 carried with a screw 0 which'is threaded diametrically through a cylindrical nut p journalled in the bracket i to rock on a horizontal axis to accommodate the aforesaid selfaligning of the spring; The worm 0' may he disposition of the spring 70 with respect to the a be threaded in or out'of the nut 72 to adjust part directly beneath the point of pivotal attachment of the hanger i to the bracket 2".

Displacement of the tubular axle from this relationship is resisted by the spring A: which may momentarily from time to time take a component of the, load.

The assembly described is such that the axles c, d of the, wheels 0, may move about the stub axlef; the stub axle 7 may move about the dead axle h; and the dead axle k may swing about the point of pivotal att achment of the hanger i on the bracket 71.

These movements ingreater of less extent will result from different conditions of operation and the combining of the movements will give the most eihcient action free to a great extent from injurious shocks. The

springs in and n are constantly in action to restrain these movements toa desired degree.

Referring now to the" improved form ofv drive illustrated in Figures 6 and 7 it will be seen that the track b is made up of a plurality of pivoted links 6, every other one of which, in the illustrated embodiment, has a depending lug bl The lugs 6 guide the track in its movement over the dual wheels 0 and Y bolts g,respectively, which may serve to sea. The fellies b and b of the driving wheel 32 are spaced to receive therebetween a plurality of rollers g journalled revolubly on cure the felly members together. As shown, each roller has a concave periphery 9 which is adapted to engage the driving edge of the lugs b, which is convex in form to insure the Ill! most satisfactory interaction with the periphery of the roller. It will be evident, however, that each roller may be fiat on its 'peripheryin which case the driving edges of the lugs will, similarly, be flat. Since the rollers may revolve, their engagement with the lugs may be maintained without surface friction, a rolling contact being provided. This results me more efficient drive with minimum loss of power. Further, the wheel construction itself insures free scavaging, since the space between the rollers is open and their constant rotation will serve to discharge material. Radial spokes b, which support the telly b, are so related to the parts as not to interfere with this action and the web of the other felly b may have openings b therethrough ad ace nt the periphery of the rollers to further the discharge of material.

Changes in the matter of design, material and relative disposition of parts may be made without departing from the spirit of the invention, so long as the results indicated herein are obtained by elements responding to the appended claims.

What I claim is:

'l. in a convertible road vehicle having steering wheels, in combination, a load wheel on each side of the vehicle, two additional load wheels on each side of the vehicle and mounted independently of the first load wheels, a rigid frame in which the two last named wheels at each side of the vehicle are j ournaled, means to connect said frame pivotally with the frame of the vehicle, and springs operatively inter osed between the two frames to resist yiel ingly relative displacement therebetween.

2. A vehicle having a load wheel, an additional load wheel, a dead axle carried with the vehicle frame, means to mount the additional wheel on said axle, a spring between the frame of the vehicle and said dead axle to resist yieldingly displacement of the axle with respect to said frame, and a spring between the mounting means and the frame.

3. A vehicle having a load wheel, an additional independently mounted load wheel, a dead axle carried with the vehicle frame, an arm carried with the dead axle on Which said additional load wheel is mounted, whereby the additional load wheel may have an arcuate movement about said dead axle, a spring operatively interposed between said arm and the frame of the vehicle to resist said arcuate movement, and a spring between the frame of the vehicle and the dead axle.

4. A vehicle having a load wheel, an additional load wheel, an arm upon which said last named wheel is mounted, a lever journaled on the frame, a dead axle mounted on the lever, means to journal the arm on the dead axle, whereby the last named Wheel may have an arcuate movement about said dead axle, a spring operatively interposed between the arm and the frame of the vehicle to resist said arcuate movement, and an independent spring between the lever and the frame to resist yieldingly movements of the dead axle toward the first named load wheel.

5. A vehicle having a load wheel, an additional independently mounted load wheel, an arm upon which said last'named Wheel is mounted, a dead axle carried with the vehicle frame, means to pivotally suspend the dead axle from the frame of the vehicle, means to journal the arm upon the dead axle, a spring interposed overatively between the frame of the vehicle and the dead axle, suspending means to resist yieldingly movements thereof, and a spring between the arm and the. frame.

6. A vehiclehaving a load wheel, a dead axle pivotally suspended from the frame of the vehicle. independently of the load wheel, an arm pivotally mounted on the dead axle and carrying at its free end a stub axle, a

bogey frame pivoted on saidstub axle, wheels journaled in the bogey frame at opposite sides of the stub axle, spring means operatively interposed between the frame ofthe vehicle and the bogey to resist yieldingly displacement of the bogey with respect to the frame, and a spring between the dead axle and the frame.

7. A vehicle having a load wheel, a dead axle pivotally suspended from the frame of the vehicle independently of the load wheel,

an arm pivotally mounted on the dead axle and carrying on its free end a stud axle, a bogey frame pivoted on said stub axle, wheels journalled in the bogey frame at opposite sides of the stub axle, a lever pivoted on the frame and engaged with the dead axle and a spring operatively engaging the said lever to urge the dead axle yieldingly away from the first named load wheel.

8. A vehicle having a load wheel, a dead axle pivotally suspended from the frame of the vehicle, an arm pivotally mounted on the dead axle and carrying at its free end a stub axle, a bogey frame pivoted on said stub axle, wheels journalledin the bogey frame at opposite sides of the stub axle, a lever pivoted on the frame and engaged withthe dead axle, a spring operatively engaging the said lever to urge the dead axle yieldingly away from the first named load wheel and a spring operatively interposed between the said arm load.

and the frame ofthe vehicle to cushion the j 9. A vehicle having a load wheel, a dead axle pivotally suspended from the frame of A the vehicle, an arm" pivotally mounted on the dead axle and carrying at its freelend a stub axle, a bogey frame pivoted on said stub axle, wheels journalled in the bogey frame at opposite sides of oted on the frame the stub axle, a lever pivand engaged with the dead axle, a spring operatively engaging the said lever to urge the dead axleyieldingly away from the first named load Wheel, a spring peratively interp0sed bet'ween the said arm and the frame of the vehicle to cushion the load and means to adjust the tension of said springs.

' April A. D. 1928 WALTER CHRISTIE. 

